Various livestock identification methods are known and have been used for owner-ship marking and animal tracking purposes. Disease control, food safety, and supply chain management have produced regulations that mandate positive and unique identification. Herd population growth has necessitated development of automated identification technologies for management efficiency.
Radio Frequency Identification (RFID) is one such method of automated identification that has gained acceptance of regulatory agencies and is currently widely deployed. While several alternate RFID technologies exist, the passive transponder that operates at low frequency (“LF”—134.2 KHz) is the dominant type.
Early passive transponders included large electronic assemblies that were suspended from collars placed around animal necks, such as is depicted in FIG. 1 (104). As technology improved and application specific integrated circuits were developed, transponder form factors diminished. One current tagging method is an eartag (102) which usually includes a front section with visual marking, and a rear section retainer which houses the electronic passive transponder.
While an ear tag provide an effective means of unique identification, some agencies have adopted transponders encased in a bolus form factor, suitable for ruminant livestock. As shown in FIG. 1, the bolus (103) is placed in the ruminant's stomach, where it is retained for the duration of the animal's life. Installation in this location also provides the potential to collect animal physiological data, such as the animal's body temperature, and such applications have been disclosed in the prior art.
The passive transponder with temperature monitoring capability provides a useful means of unique identification and animal health monitoring, but is limited in several ways: (1) the animal must be proximal (typically within 1 meter) to a LF transponder scanner in order to collect identification and temperature data; (2) because the transponder has no integral power source, it cannot autonomously record temperature data for batch conveyance to the scanner at a later time; and (3) without sufficiently frequent temperature measurements, the value and significance of temperature data is greatly compromised.